Info about JDM vs USDM y21 or s80 transmission

There are many differences between the JDM and USDM transmissions on Honda b-series engines. Here are some of the things I discovered while rebuilding several transmissions.

Shift fork pivot ball sizes
Shift fork pivot ball sizes
Transmission oil fill bung sizes
Transmission oil fill bung sizes


Click for more information on the Transmission oil fill bung sizes


Transmission shift fork
Transmission shift fork

This is the fork that pushes the pilot bearing that moves the clutch away from the flywheel. The pivot ball goes under this fork and adjusts the movement of the fork.


View inside shift fork hole into transmission
View inside shift fork hole into transmission

You can see the pivot ball bolted in right there. I was using the incorrect one, and had difficulty adjusting the clutch properly… I had to remove the transmission from the car to change this!


Another view of the pivot ball
Pivot ball removed
Here are the two size pivot balls I have
The larger one has an indentation on the top.

Shift fork pivot ball measurements:

Width of smaller pivot ball
Width of larger pivot ball
smaller pivot ball socket size: 19mm
Larger pivot ball socket size: 21mm
Larger pivot ball height: 26mm
Smaller pivot ball height 24mm

Don’t forget while your in the transmission to clean the magnet!!!

Magnets removed from transmission case (Just pry it up and it pops out)
Another view where the magnet is at.
The dirty magnets! filled with metal shavings!
Now they are clean, and ready to reinstall. They just push right back in place